Siemens SINAMICS S120 Function Manual page 161

Operating states
The following operating states are possible for DSC (for details, see function diagram 3090
in the SINAMICS S120/S150 List Manual):
Operating state for DSC
Speed/torque precontrol with linear
interpolation
Speed precontrol with splines
Speed/torque precontrol with
splines
1)
2)
Activation
If the preconditions for dynamic servo control are fulfilled, then the DSC structure is activated
using a logical interconnection of the following parameters via a selected PROFIdrive
telegram:
● p1190 "DSC position deviation XERR"
● p1191 "DSC position controller gain KPC"
● p1194 "CI: DSC control word DSC_STW"
● p1195 "CI: DSC symmetrizing time constant T_SYMM"
● p1430 "CI: Speed precontrol"
If KPC = 0 is transferred, only speed control with the speed precontrol values can be used
(p1430, PROFIdrive N_SOLL_B and p1160 n_set_2). Position-controlled operation requires
a transfer of KPC > 0.
Drive functions
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
1)
The following improvements are achieved as a result of spline interpolation:
- A finer interpolation of the torque in the speed controller cycle and so smoother movements and
the avoidance of the impact torques.
- Very high path accuracy for torque speed precontrol (i.e. smaller following error in the control
behavior).
- High-frequency path movements are possible
For active symmetrization (T_SYMM > 0), using p1427 you can set an additive symmetrizing time
constant T_SYMM_ADD to symmetrize the speed precontrol value when torque precontrol is
active.
In this case, the speed precontrol value is symmetrized with the sum of the following time
constants:
T_SYMM (see p1195) + T_SYMM_ADD (p1427) + 0.5 × T_speed_controller_cycle (p0115[1])
The speed generation is considered automatically using the position differences with a half speed
controller cycle.
Meaning
As a result of the step-like torque precontrol in the position
controller cycle, a pulsed torque characteristic is obtained with
the excitation cycle.
1)
The position setpoint is made symmetrical.
•
The speed precontrol value is not made symmetrical.
•
The position setpoint is made symmetrical.
•
The speed precontrol value is made symmetrical.
•
The torque precontrol value is not made symmetrical.
•
Servo control
4.16 Dynamic Servo Control (DSC)
2)
161